Abdominal Distension: (fu zhang 腹脹, pi man 痞滿)

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Article originally published November 18, 2018

Excerpted from the Clinical Handbook of Internal Medicine by Maclean, Lyttleton, Bayley & Taylor

Fu zhang refers to a sense of fullness, discomfort, blockage or obstruction across the either the upper or lower abdomen, or across the abdomen as a whole. Pi man is distension specifically in the epigastric area. For practical purposes, however, fu zhang and pi man can be dealt with as a single TCM defined disease symptom, henceforth abdominal distension, because the pathology and treatment strategies are generally the same.

The complaint of distension, often described as ‘bloating’,'fullness' or 'discomfort', usually refers to a subjective feeling of fullness or pressure within the abdomen. It may or may not be associated with visible swelling of the abdomen. In practice, abdominal distension can be difficult to localize to a specific area, and will frequently be felt in different places. When the disease diagnosis is abdominal distension, the distension is generally not associated with pain.

Distension may be acute or chronic. When acute it is usually due to dietary indiscretion, or is part of an external invasion. Patients with chronic patterns are the ones most likely to present in clinic, and this chapter focuses on these, often difficult, prolonged patterns.

As a general rule, abdominal distension is due to an obstruction to the correct movement of Spleen and Stomach qi. The obstruction itself may be due to the presence of some pathogen, internal or external or due to weakness or stagnation of qi.

In TCM terms, there are four main mechanisms that can produce abdominal distension, each of which can occur separately or in combination. These are:

• obstruction of the qi mechanism
• fluid retention
• constipation
• pathogenic accumulation (usually Phlegm and/or Dampness)

In practice, these mechanisms are often intermingled, and become mutually engendering. For example, if the qi mechanism is obstructed by a pathogen (say Damp or stagnant food from the diet), this can eventually weaken the Spleen, which then fails to regulate and distribute fluids adequately. These now pathogenic fluids accumulate in the tissues of the abdominal wall and Intestines, aggravating the distension. Similarly, obstruction of the qi mechanism is often complicated by constipation, as Stomach qi fails to descend and aid the passage of stool. With a constipated stool, qi backs up through the digestive tract, further obstructing qi movement and disabling the qi mechanism.

ETIOLOGY

Diet, Food stagnation

Food stagnation is a common component of abdominal distension. Eating more food than the Spleen and Stomach can cope with, either because too much is consumed, or because the Spleen is already weak, will obstruct the qi mechanism and thus the descent and ascent of middle jiao qi. Once the qi mechanism is obstructed by unprocessed food, various complications can arise to further aggravate the distension. One of the most common complications is constipation. Thus disruption of the qi mechanism, food stagnation and constipation form a common clinical picture.

Overeating, eating irregularly or at odd hours, especially late at night, weakens Spleen and Stomach qi and leads to food stagnation. Too much cold natured or raw food weakens Spleen qi and yang. Overconsumption in general and excessive consumption of rich, heating and supplementing foods in particular, can lead to the accumulation of food and Damp Heat in the Intestines.

Food stagnation is a common precursor to a large number of other pathologies and is a common etiological factor in the development of many of the diseases that occur in modern life. In traditional TCM texts food stagnation as a cause of disease has been underrated because overeating or a rich diet was not common among the Chinese people. However, in developed countries in modern times, food stagnation is more common and more insidious. Patients can become conditioned to ignoring, or may not even be conscious of, the typical symptoms of bloating, belching, bad breath, and flatulence. The eating patterns that give rise to such symptoms may be so ingrained that individuals cease to be aware of them, or the symptoms experienced are considered to be normal.

By habitually overloading the Spleen and Stomach and exceeding their capacities to process the food ingested, a cycle is begun that can have profound ramifications. Firstly, instead of being sent through the Intestines, the food lingers longer than it should, fermenting and rotting. The stagnation in the digestive tract may produce Heat which can intensify this process of putrefaction. The Spleen and Stomach are weakened, further inhibiting their abilities to perform their digestive tasks efficiently. The weakened Spleen produces Damp which in turn may be congealed into Phlegm by the Heat. The Phlegm or Phlegm Heat so produced can then affect other systems, for example the cardiovascular system (Phlegm stagnation in the chest causing chest pain), neurological system (some types of tremors, anxiety states, insomnia, vertigo, paralysis) and skin (cysts, various ulcerations, chronic sores and swellings). In addition, chronic Heat or Damp Heat can injure Intestinal yin and the Intestinal lining, compromising the circulation of qi and Blood. Phlegm accumulation may eventually evolve into Blood stagnation, causing polyps, nodules and tumors.

Emotion

Liver qi stagnation is a common component of recurrent abdominal distension. It impacts on the abdomen in numerous ways. Liver qi can invade the Spleen and Stomach and disrupt the qi mechanism. It can impair the Spleen's ability to process fluids, resulting in fluid accumulation in the abdominal wall and Intestines, or in development of Dampness and Phlegm from the retardation of fluid movement. Qi stagnation can slow the passage of food through the Intestine, causing constipation and distension.

Prolonged or severe Liver qi stagnation can also generate stagnant Heat, which can then combine with any Dampness present to form Damp Heat, or can injure fluids and yin.

Liver qi stagnation is caused by repressed emotion, frustration, anger and resentment.These emotions, especially when chronically unexpressed, cause a low grade spasm and tension in the smooth muscle of the gut. Patients with chronic qi stagnation type digestive problems will often note that their stress and tension is stored in the gut and be aware of the consequences of stress - the knot in the stomach, stomach cramps, loss of appetite and bowel disturbances. Liver qi stagnation type distension tends to be intermittent and is clearly related to the emotional state and stress levels of the patient.

In addition to the emotional factors that upset the Liver, worry, obsessive thinking and prolonged concentration, in combination with a sedentary lifestyle and poor diet, will weaken Spleen qi, predisposing it to (or inviting) invasion by Liver qi. This may result in further damage as well as disruption to the qi mechanism. Spleen qi naturally ascends creating the appropriate equilibrium for the descent of turbid waste materials, so it is said the Spleen governs 'the raising of the clear and descent of the turbid'. If this activity fails, the qi and 'clear and turbid' (turbid here implying Dampness as well as waste materials) intermingle and accumulate, causing a feeling of fullness and distension.

Dysfunction of the Lungs can also contribute to abdominal distension. Bereavement, social isolation, unresolved issues of loss or abandonment and sudden changes of familiar routine are all factors which can cause Lung qi to knot up and accumulate. Because the Lung system incorporates the Large Intestine, qi accumulation and constipation can result.

If Lung qi has been weakened through illness or lack of exercise, a similar situation may arise. Weak Lung qi may not descend because it is too feeble to do so. When the Lungs are involved in the genesis of distension, there is often a postural component as well. Lung disorders frequently cause patients to hunch forward, slouching over and rolling their shoulders internally. This further restricts the free movement of Lung qi and compounds the accumulation.

Spleen and Stomach deficiency

Spleen and Stomach weakness is at the root of many cases of abdominal distension, and can contribute to all patterns. In simple cases, the Spleen is weak and unable to process food adequately; gu qi is not sent to the Lungs and accumulates in the middle jiao causing distension. Similarly Stomach qi may fail to descend, compounding the distension and contributing to constipation. This is a deficiency type of qi mechanism blockage.

Other aspects of Spleen and Stomach weakness may complicate the basic pattern. When the Spleen fails to move and metabolize fluids, the fluids may accumulate in and around the tissues of the abdominal wall or Intestines. Fluid accumulation is a common cause of generalized abdominal distension. In contrast to the qi blockage type of distension, fluid retention is more widespread and not focused in a specific region (such as the epigastrium). On its own, fluid accumulation tends to lack the typical gastrointestinal clues that characterize qi blockage, such as frequent belching, flatulence or constipation. Fluid accumulation type distension also tends to be more prolonged and harder to shift than qi blockage. It seems to affect females more frequently than males.

A weakened Spleen may generate Dampness and Phlegm. Dampness and Phlegm are especially good at creating obstruction, and, once present, easily block the qi mechanism, aggravating the condition.

A weak Spleen can also 'invite' the unwanted attentions of a normal Liver, causing qi stagnation and further disrupting the qi mechanism.

Spleen qi and yang are weakened by excessive consumption of cold raw food and irregular eating habits, or by too many cold natured herbs or antibiotics in the treatment of a febrile or other hot disease. Additional factors are lack of physical activity, prolonged or serious illness, and prolonged starvation or digestive insults as occurs in patients with a history of anorexia nervosa or bulimia.

Pathogens

Various pathogens, both internal and external, can contribute to patterns which include abdominal distension. External invasion of Wind (plus Cold, or less commonly, Heat) can obstruct the natural descent of Lung qi causing disruption to the qi mechanism. What this means is that when Lung qi is obstructed and prevented from descending naturally, this influences the natural ascent of Spleen qi. Qi begins to accumulate in the middle jiao and this is experienced as distension.

External Damp Heat can invade the Spleen and Stomach, indeed Damp has a preference for lodging in the gastrointestinal system. Once in the body it often accumulates in the middle jiao blocking the qi mechanism.

Internally generated Dampness, Phlegm or Damp Heat may be the product of qi blockage applied to physiological fluids, congealing them over time. Dampness caused by ingestion of an excess of dietary Damp inducing agents, or Spleen weakness that creates Damp, may block the normal movement of middle jiao qi.

Constipation

Constipation is a common contributing factor in abdominal distension, both generally over the abdomen as a whole, and specifically over the site of the constipated stool. Constipation itself can be related to qi obstruction - if qi is not descending there is no impetus behind the stool to move it forward and out; similarly if the stool isn't moving, qi will back up behind the obstruction.

TCM DIFFERENTIAL DIAGNOSIS

• Gu Zhang (臌張, ascites, or drum like abdominal distension): Gu zhang, or ascites, is characterized by fluid accumulation in the abdominal cavity, with a decrease in urinary output. The abdomen may be quite distended, however the presence of fluid distinguishes ascites from simple abdominal distension. Gu zhang is a sign of serious disease, and occurs in such conditions as hepatic cirrhosis, congestive cardiac failure, abdominal and liver cancer, schistosomiasis, chronic malaria and tuberculous peritonitis. The name Gu zhang (literally drum distension) derives from the resemblance of the abdomen to a drum - firm and taut on the outside and empty within - the emptiness here referring to deficiency of the various zang fu involved.
• Jie Xiong (結胸): Jie xiong describes a syndrome of the lower thorax and epigastrium characterized by focal pain, fullness and rigidity. The pain is usually the major feature. Jie xiong may be associated with biomedical disorders such as pleurisy, intercostal neuralgia and peptic ulcer disease.
• Xiong Bi (胸痹): Xiong or chest bi syndrome is a feeling of fullness, stuffiness and pain in the chest, often associated with diseases of the Heart and/or Lungs.

TREATMENT

Treatment involves determining precisely which mechanism (or combination of mechanisms) is at play. When the qi mechanism is disrupted, the correct ascent and descent of qi must be promoted, in addition to dealing with the underlying pathology. When fluid retention is contributing to the distension, a diuretic method is employed. When constipation is an issue, a laxative, purgative or qi regulating method is used depending on the type and pathology.

Regulation of diet, the types of food ingested and the way food is eaten, is essential, as all other treatments will be less than completely successful if this fundamental component of gastrointestinal health is neglected.

Exercise is important in the excess patterns, especially when Liver qi stagnation or qi accumulation is involved. Exercise moves qi and strengthens Spleen and Lung function. Sustained walking and deep breathing is often sufficient, at least temporarily, to move qi.